平面四旋翼无人飞行器运送系统的轨迹规划与跟踪控制器设计

Trajectory planning and tracking controller design for a planar quadrotor unmanned aerial vehicle transportation system

对于四旋翼无人飞行器运送系统而言,需要保证飞行过程中负载的摆幅维持在适当的范围内,并且在飞行器到达目的地后负载无残余摆动.本文针对四旋翼无人飞行器运送系统,提出了一种新颖的轨迹规划与跟踪控制方法.论文首先得到了平面四旋翼无人飞行器的运动特性与负载摆角之间的非线性耦合关系.通过相平面内的几何分析,分别设计了两个轴方向上的分段式加速度轨迹.这种轨迹具有简洁的解析表达式并可获得较高的运送效率,同时满足飞行器的速度,加速度等物理约束.为了使四旋翼无人飞行器准确跟踪规划好的轨迹,本文基于反步法设计了一种非线性跟踪控制器,并通过李雅普诺夫方法对其闭环稳定性进行分析,证明其能使跟踪误差指数收敛于零.论文最后通过仿真结果验证了本文所提出方法的可行性与有效性,及其对外界干扰的鲁棒性.

For a quadrotor unmanned aerial vehicle（UAV） transportation system, it is necessary to keep the payload swing within an appropriate range in the flight course, and the residual swing should vanish when the UAV reaches the destination. To meet these requirements, we propose a novel method of trajectory planning and tracking control for the quadrotor UAV transportation system. In this method the nonlinear coupling behavior between the planar motion and the load swing of the quadrotor UAV is first determined; and then, we derive a simple expression for each segmented acceleration trajectory along two planar coordinates in the phase plane. Because of their simplicities, these segmented trajectories are easy to be applied to design a backstepping-based nonlinear tracking controller for obtaining an efficient transportation course while satisfying the physical constraints on velocity and acceleration of the UAV. The stability of the closed-loop system is proved by using Lyapunov techniques, which ensures that the tracking error exponentially converges to zero.Simulation results show the feasibility and effectiveness of the proposed approach in achieving the desired performance indices while providing robustness against external disturbances.